There is an oddly familiar ring to Democrats' escalating attacks on the conservative billionaire Koch brothers.

In 2010, then-White House adviser David Axelrod decried the undisclosed, unrestricted money bankrolling outside conservative groups as “a threat to our democracy.” This year, Senate Majority Leader Harry Reid has been blasting the Kochs as “un-American” and accusing them of “trying to buy America.”

The comparison bodes poorly for Democrats now dumping millions into their campaign to demonize the Kochs in what appears to be a central piece of their midterm elections strategy. In 2010, unrestricted conservative outside groups funded by industrialists Charles and David Koch helped knock House Democrats out of power in a historic GOP upset. This time around, the Koch-funded Americans for Prosperity has already spent some $27 million attacking Democrats, focusing squarely on the party’s most vulnerable Senate incumbents.

But it’s unclear how much Democrats have learned from the last midterms. Yes, Democrats have established their own network of unrestricted super PACs, casting off any pretense of taking the political-money high road. This election’s top-spending super PAC so far is the pro-Democrat Senate Majority PAC, according to the Center for Responsive Politics, and liberal super PACs have spent almost double that of their conservative counterparts.

The anti-Koch attacks are now the subject of a $3 million Senate Majority PAC ad campaign — essentially a retread of liberal assaults on big money in 2010. In those elections, the first to follow the Supreme Court’s ruling in early 2010 to lift all limits on independent political spending, Democratic National Committee spokesman Brad Woodhouse bemoaned the “growing and pernicious effects of secret, special interest money being used to determine the outcome of our elections.”

This time, the Democrats’ attacks on big money are being leveled more personally at the Kochs and their Koch Industries Inc. conglomerate. The Democratic Senatorial Campaign Committee portrays Republicans as “addicted to Koch.” A Web ad by American Bridge 21st Century, the Democratic super PAC and tracking organization, calls the Koch agenda “bad for the middle class.”

http://www.youtube.com/watch?v=LZmhOT0LzFs

Officials for Koch Industries have criticized the attacks as an intimidation campaign designed to deflect attention from Democrats’ own agenda. Organizers for Americans for Prosperity, a social welfare group that operates outside the disclosure rules, maintain that their objective is to repeal the Affordable Care Act.

But the group's ads hammer on vulnerable Democrats in states such as Arkansas, Louisiana and North Carolina, and they are expanding into campaign-style organizing, door-knocking and voter mobilization. Some speculate that the anti-Koch attacks leveled by Reid and his allies are a distress signal to liberal donors.

Democrats say their complaints against the Kochs are rooted in their policy differences with Republicans. The anti-Koch campaign hammers on populist themes such as economic equity and entitlements for seniors, and portrays Republicans as the party of moneyed interests.

As American Bridge spokeswoman Gwen Rocco put it: “The real reason the Kochs have already spent tens of millions on attacks this cycle is to undermine voters’ confidence in government and drive their conservative agenda that enriches the wealthiest Americans at the expense of the middle and working class.”

In Arkansas, where GOP Rep. Tom Cotton is challenging incumbent Democratic Sen. Mark Pryor, Pryor campaign officials estimate that Americans for Prosperity has spent $2.2 million on ads opposing the senator. Total outside spending against Pryor tops $5 million. Pryor accuses Cotton of being in the pocket of wealthy interests and argues that the representative's votes against the farm bill and the Violence Against Women Act, for example, put him and the conservative groups that back him out of step with Arkansas voters.

“Obviously the outside money from these Republican groups is going to be large, and it’s likely that we will be outspent on TV,” Arkansas Democratic Party spokesman Patrick Burgwinkle said. “But what’s important for us is getting the message across that Congressman Cotton and these outside groups are just too reckless for Arkansas.”

In North Carolina, Democratic Sen. Kay Hagan has launched a digital media campaign showing her GOP opponent, state House Speaker Thom Tillis, as aligned with the Kochs' “bad-for-the-middle-class” policies. Americans for Prosperity has spent $8.3 million on ads opposing Hagan, according to numbers released by Hagan's campaign.

Republicans dismiss the anti-Koch attacks as a sign of Democratic desperation. In 2010, voters largely ignored Democrats’ assaults on secret, unrestricted campaign money and delivered the House to Republicans in a 68-seat sweep. Democrats’ recent anti-Koch assaults are more rooted in substantive differences with Republicans on issues such as Medicare and the minimum wage. Still, it remains to be seen whether their campaign against moneyed interests will resonate any better with voters in the 2014 midterm elections than it did four years ago.